Agents could not go into details of the allegations but said the threat included the Huntsville and Madison County area, including Redstone Arsenal.

"We do not discuss the installation's security conditions. We always appreciate the close work and cooperation within our law enforcement community which keeps Team Redstone safe and secure each and every day," said Chris Colster, U.S. Army Garrison, Redstone Arsenal spokesman.

Agents said there is no standing threat.

Roger Stanton, Special Agent in Charge of the FBI's Birmingham Division, said this has been a joint investigation. That investigation is ongoing.

Police confirmed the investigation is connected to an apartment at Twickenham Village Apartments on Galaxy Way. Police say this is where Sayyed was allegedly staying. They executed a search warrant at the apartment on Thursday.